chapter19_updated

chapter19_updated - 2/14/2009 1 Magnetism Loud speaker,...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 2/14/2009 1 Magnetism Loud speaker, microphone, earphone Hard drive Credit card Video/audio tape; /floppy/zip disk Electric generator/motor Bullet train Hybrid cars; 2/14/2009 2 Cruise Control Mirror Motors TailGate Motor Door Lock Motor Four Wheel Steering Anti-skid Sensor and Motor Window Lift Motor Suspension System Fuel Pump Motor Chip Collector Seat Belt Motor Seat Adjust Motors Antenna Lift Motor Traction Control Heat-Air Condition Motor Throttle and Crankshaft Position Sensors Windshield Wiper Motor Starter Motor Coolant Fan Motor Ignition Systems Headlight Door Motor Economy and Pollution Control Liquid Level Indicators Windshield Washer Pump Gauges Tape Drive Motor Head Rest Motor Sun Roof Motor Electric Power Steering and Sensor Lumbar Support Automatic Temperature Control Door Gasket Defogger Motor Speakers Auto Motors with permanent magnets PM Motors per car (avg.) 2000 : 25 2005 : 32 A magnet always has two poles , called north and south , at the same time Like poles repel, unlike attract each other Similar to electric charges A compass is a small piece of magnetic pointer free to align itself with a magnetic field 2/14/2009 3 A magnet produces a magnetic field A vector quantity; symbolized by Direction is given by the direction a north pole of a compass needle points in that location Magnetic field lines can be used to show how the field lines, as traced out by a compass, would look In addition to permanent magnets, moving charge (electric current) also includes a magnetic field (discussed later) B Similar to the field of a positive and a negative charge (electric dipole) Arrows give direction Density gives strength x x x x x x x x INTO Page OUT of Page 2/14/2009 4 Iron filings are also often used to show the pattern of the magnetic field lines Compared to field lines of electric charges Magnetic poles cannot be isolated If a permanent magnetic is cut in half repeatedly, you will still have a north and a south pole This differs from electric charges N S N S N S Break it up 2/14/2009 5 An unmagnetized piece of iron can be magnetized by stroking it with a magnet Magnetism can be induced If a piece of iron is placed near a strong permanent magnet, it will become magnetized Soft magnetic materials, such as iron, are easily magnetized; their magnetization directions are easily changed They also tend to lose their magnetism easily Widely used in electric transformers Hard magnetic materials, such as cobalt and nickel, are difficult to magnetize (all permanent magnets are made of hard magnetic materials) They tend to retain their magnetization X 2/14/2009 6 The Earths magnetic field resembles that of a huge magnetic bar The Earths geographic north pole corresponds to a magnetic south pole ; its geographic south pole corresponds to a magnetic north pole The earths magnetic filed direction...
View Full Document

Page1 / 32

chapter19_updated - 2/14/2009 1 Magnetism Loud speaker,...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online